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September 2, 2005

Fluorescent animals surprise Gulf of Mexico divers

by Sam Savage

By Maggie Fox, Health and Science Correspondent

WASHINGTON (Reuters) - Fluorescent shrimp, crabs that
detect ultraviolet light in the sunless depths, and an unseen
creature that tumbled a massive camera have surprised
scientists diving in the Gulf of Mexico.

Their expedition has turned up an array of creatures that
use fluorescence in ways previously unknown to science, the
team, a collaboration of federally funded researchers, said on
Friday.

The discoveries suggest that even animals living with no
light from the sun can detect and use light, perhaps for
hunting, mating and other purposes, the researchers report on
their Internet Web site, http://oceanexplorer.noaa.gov.

"This is incredible because these animals are found down at
1,800 feet," said chief scientist Tammy Frank.

"As far as we know there is no ultraviolet light down
there," Frank added in a telephone interview from aboard the
team's ship in the Gulf of Mexico.

"If they are ultraviolet-sensitive the question is what the
heck are they doing with it?" said Edith Widder of the Harbor
Branch Oceanographic Institution in Ft. Pierce, Florida and the
private Ocean Research and Conservation Association.

"We are barely scratching -- I was going to say the surface
but the bottom would be more appropriate."

The National Oceanic and Atmospheric Administration funded
the expedition to sites around the Gulf of Mexico. The
researchers had to divert to Galveston, Texas to avoid
Hurricane Katrina last week, but left an undersea camera to
record the undersea activity.

Frank said she designed a special red-light camera that
would not frighten away or blind the extremely light-sensitive
creatures that live so far from the light.

"We are exploring the deep sea with new eyes," Frank said.

"Traditionally, most of seep sea operations use bright
white light, which really disturbs the behavior of the
animals."

The camera weighs about 200 pounds (90 kg) and is mounted
on a 7-foot (2-meter) apparatus, so the researchers felt safe
leaving it unattended.

When they returned after the storm had passed, the camera
was upside down.

"We don't think it was Katrina because it was 1,700 feet

down," Widder said. "I think a large predator got hold of
it."

The team has also photographed a fluorescent shark and said
large sharks have attacked the camera in the past.

Mike Matz, of the University of Florida's Whitney
Laboratory in St. Augustine, said a variety of animals have
been found to use fluorescence, usually only seen in animals
living at shallower depths.

"Those are little crustaceans, shrimp and planktonic
copepods," he said. The light-emitting effect is seen in their
eyes, on spots on their tails, at the leg joints and on the
antennae," he said.